Conventionally, contact probe units have been widely used for testing electroconductive patterns of printing circuit boards and various electronic devices, and there have been attempts to modify them into more suitable forms for testing LCD panels. In testing an LCD panel, it is desirable to test it at a condition which closely simulates the actual condition of the final product, and it is therefore desirable to test the LCD panel by using a TAB (an LSI chip used for driving an LCD panel) identical to that used in the final product. Because a large number of wires must be connected between the LCD panel and the TAB, preferably, the TAB should be incorporated in the contact probe unit itself.
However, the TAB may have to be replaced from time to time either due to a failure of the TAB or a change in the specification of the product. If the TAB is connected to the contact modules by soldering, a substantial amount of work is necessary for replacing the TAB. Also, soldering tends to produce a large amount of foreign particles, and it is detrimental to the clean room environment in which LCD panels are produced. Therefore, when replacing the TAB, it would be necessary to take the contact probe unit out of the clean room environment, and replace the TAB. Furthermore, it would be necessary to thoroughly clean the contact probe unit before bringing the contact probe unit back into the clean room.
In some of the contact probe units proposed by the present inventor and disclosed in the above mentioned patents and patent applications, each contact module comprises a compression coil spring received in a support hole or a tubular receptacle, and a pair of needle members attached to the corresponding ends of the compression coil spring to urge them outward. The extent by which each of the needle members projects from the corresponding end of the support hole or the receptacle is determined by suitable stopper means. The inventor has considered the possibility of adapting such contact probe units for incorporating a TAB in such a manner as to allow replacement of the TAB in a simple manner.